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Appendices
Appendix 6 Criteria for ranking likelihood and consequence to the Region’s values
A standard set of criteria allows the comparison of different types of threats within the one risk assessment, based on the likelihood and consequence of each threat. The likelihood and consequence of each predicted threat are ranked on the five-point scales described below.
Likelihood scale
Likelihood Almost certain Likely Possible Unlikely Rare Expected frequency of a given threat Expected to occur more or less continuously throughout a year Not expected to be continuous but expected to occur one or more times in a year Not expected to occur annually but expected to occur within a 10-year period Not expected to occur in a 10-year period but expected to occur in a 100-year period Not expected to occur within the next 100 years
Consequence scale
Based on current management Ecosystem Broad scale Impact is clearly affecting, or would clearly affect, the nature of the ecosystem over a wide area. Recovery periods greater than 20 years likely. Impact is, or would be, extremely serious and possibly irreversible to a sensitive population or community. Local scale Heritage Impact is or has the potential to destroy a class or collection of heritage places on a large scale; or is clearly affecting, or would clearly affect, a range of heritage values over a wide area. Impact is, or would, adversely affect the heritage values of a number of places; destroy individual heritage places of great significance; or significantly affect the heritage values over a wide area. Impact is, or would, affect individual heritage places or values of significance; or affect to some extent the heritage values at a wider scale. Impact is, or would, affect heritage places or values of local significance, but not at a wider scale. Impact would not impair the overall condition of the heritage values. No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the heritage values; or positive impact.
Consequence
Catastrophic
Major
Impact is, or would be, significant at a wider scale. Recovery periods of 10 to 20 years likely.
Condition of an affected part of the ecosystem possibly irretrievably compromised. Impact is, or would be, serious and possibly irreversible over a small area. Recovery periods of 10 to 20 years likely.
Moderate
Impact is, or would be, present at a wider scale, affecting some components of the ecosystem. Recovery periods of five to 10 years likely. Impact is, or would be, not discernible at a wider scale.
Minor
Impact would not impair the overall condition of the ecosystem, or a sensitive population or community, over a wider level. No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the overall condition of the ecosystem.
Impact is, or would be, significant to a sensitive population or community at a local level. Recovery periods of five to 10 years likely. No impact; or if impact is, or would be, present then only to the extent that it has no discernible effect on the overall condition of the ecosystem.
Insignificant